Only the top 18 riders continue on to the freestyle portion of the competition on Thursday. In the previous Olympic test Aug. 2, Rafalca and Ebeling earned a score of 70.2.

Ebeling and Rafalca danced to a mix of traditional and fast-paced music, and Ebeling took off his top hat and beamed at the conclusion of Tuesday's ride in Greenwich Park. The weather looked chilly as audience members bundled up. But there were still plenty of American flag wavers in the stands to cheer them on.

They faced stiff competition from many of the riders, especially some of the "stars of dressage," including Britain's Charlotte DuJardin and her horse Valegro, who earned a stunning 83.66 last week and hope to bring home Britain's first gold in dressage ever.

Patty Lasko, the editor of Dressage Today, told ABC News that sometimes those watching see things the judges miss, and she thought Ebeling and Rafalca's performance last week was "wonderful," emphasizing that any score above 70 percent means a strong performance, especially for first-time Olympians.

"They were great. ... Those of us who are not judges don't always see what they see or go with what they seem is right, but I thought he did wonderful," Lasko told ABC News. They should be very proud, and that score is a very credible score."

Of course, it's not just dressage fans closely monitoring how Rafalca performs, it's veepstakes watchers, too. It was believed that Mitt Romney would not pick a running mate until Rafalca and Ebeling were out of the competition so that Ann Romney could return to the United States. The photograph of the two families - the Romneys and the running mate - side by side is something a campaign would likely not pass up.

Romney, who has said riding helps relieve her multiple sclerosis symptoms, said she was "thrilled to death" after their first performance. She was diagnosed with MS in 1998 and began riding again, after initially riding as a child, soon after.

Although it is celebrating its 100th year as an Olympic sport, dressage, also known as horse ballet, was until recently relatively unknown in the U.S. Not anymore. The attention the Romneys have brought to the sport even had satirist Stephen Colbert calling it the "sport of the summer." The equestrian discipline gained more attention than any of its enthusiasts could have anticipated when Rafalca made the Olympics cut in June.

Ebeling and Romney co-own the German-born 15-year-old Oldenburg mare with Beth Meyer. Ebeling, a German native, became a U.S. citizen in 1998. Before competing, he doesn't let anything shake his focus -- not the campaign and not the media attention. He doesn't even speak to anyone on performance days.

"Once I get into my zone, I don't see anything, I don't hear anything. Everything is shut out," Ebeling told NBC News after his performance last week, which was one of the longer breaks between dressage competitions in recent Olympic history.

Foremost dressage expert Kenneth Braddick told ABC News there are both positives and negatives to the long wait between the initial performance on the Aug. 2 and today's competition.

"There's more time to fix whatever mistakes might have been or improve up on them, but the bad side is it's never happened this way before," Braddick said, noting the competition is usually over two days and the "huge gap" there means plenty of time for "head games" and "sitting around getting tense." And just as Rafalca and Ebeling possibly try to improve over the gap, their competitors will as well.

"The worst thing you can do in a sport is overthink and this time they have a lot of time to think," Braddick said.